Compression fitting



A981 7 1945' C. A. NORGREN. 2,381,554.l y soMPREssIoN FITTINGSA Filed Aug. 2'), 1942 FIG. 4

FIG.

FIG. 5

\ FIG. s

INVETOR.

- Gar! A. Nurgrcnv ATTO NEY Y y Patented Aug. 7, 1945 Q I v-I' if STATE s PATENT ofFFl-cs y ooMPREssroN FITTING. y l y A. Norkgren, Denver, Colo.

` *i Application August 27, 19.42,- seria1N0..456,se77

' s claimsl (C1. 285-120) This invention relates tojl'ock` joint couplings kand:relates-moreparticularly to compression ttingsyforfattachmentr of'Y flexible metallic tubing to various,objects.:v y

Inrecentg: years, exible metallic tubing; 4usually copper; has come intol widespread use vin many industrial applications; Copper, being. a ductile material, tendsto hardenfinlany place it is bent ory moved toA an appreciable degree; Consequent- 1y, anyLfastening-Which'severely distorts-the metal of. the tubing-in order to form agsealed union therewith, increases the tendencyof the metal to break: at the :point or points :Where-it is subjected to: the Igreatest stresses from `vibration and similar causes y 1 Likewise, couplingswhichdistort the metal of thetubing to anappreciabledegree cause the inner surfaceof thetube to be deformed and thuscut down theeiTective area' of thepassage and increase friction inthefmovement of iluids therethrough. y n 1 f .l y y y `It isf-Aanv; object ofthe presentk invention to provide a compression4 fitting which aiordsV an effective seal'. againstv passage of fluids without appreciable deformation ofthe wallsfofthe passage. through which the fluid flows. f

endof a rubber hose, l2.

.2 5 y'to admittubing6is screwed-on the stem and .Another object ofvthezinvention is to provide Y a. compression. member infsuch a fitting*y which maybe inserted on the tubevvith either end vfor- Ward Without .impairing function.-

l Aiurther object ofthe invention" is toprovideI acompression tting :invvhich the forces eiectingthe'sealing action areclistributedover a relatively large; area witha minimum ofdistortion resulting .in a reduction in `hardeningaction from Whichweakeningof. the ductile metal occurs'.

.I Ar still. furtherI object oi the invention is to provide a compression fitting rifn-vvhich the loosen-v ingeffect.of'vibrationsis retarded. I

Other objects. reside in noveldetails of' conf struction and. novel combinations and-y Iarrangements of parts, all of Whichl-will appear .more fullyl inthecorse ofthe following description'.r`

throughthe device of Figure 2 after compression has been applied;

Figure 4 is afragmentary section drawn to an enlargedscale, illustrating another embodiment ofi'lav compression Ymember. and associated tubing before compression; and

FigureV 5 s a. similar. through the device of Figure 4 after compression has been applied.

The couplingy ofV the. present invention, comprises .a pieceof ileXible metallic tubing 6, lat the freeend .of whichfa compression member T in the form of athick sleeve fitting closely about the tube is held in frictional engagement. The end of the tube is placedin telescoping. relation with a hollow stem, member 8, vthe outer endof which terminates .in a tapered recess 8 inv Whichcompression .sleeve l extends. v

This` stem. may be mounted on any-suitable.

object such as a valve, conduit or the like, here illustrated as .a hose. coupling l carried at. the The` stemis externally threaded, and a nut i3 .having an internallyapplies compression to sleeve member l.'

This sleeveismade ofga semi-hardmaterial, usually` brass. or steel,1which possesses sufcient resilience to tend to return to its former. position after releaseof pressure. The sleeve is relatively j heavy andis provided with one or a plurality of Toalord a better understanding of the invention-,reference Willubevmade to the accompanying drawing,l and in 'tl'iedravving' in the severalv annular grooves, lil extending deep enough into 'the ymaterialof the sleeve to permit distortion of the sleeve undery the compression influences. Ihe sleeve Athus' constitutes a series of two or more heavy ringportions and intermediate resilient deformabl'e Yconnecting portions. f

vTo further facilitate and" direct the movement of the-sleeve material underV the compression inluences'the Walls of the-grooves. lii are rounded as illustrated inFigures 2 and 4, and this curvature serves "to'directi the forcesl voi" compression towardy tube G; During the compression of the sleeve the'ring portionswhich closely surround thejutube"thus ac t as supports or guides for the connecting'portions'and compel movement ofthe connecting portions to grip and deform the tube.

As a result the tube is partially deformed in the zone in radial alinement with the grooves as indicated at lli in Figures 3 and 5, but not to a degree sufficient to materially restrict the flow and form protrudingedges il that bite into the tube l. v

fragmentary section This action serves to provide three sealing zones in the single groove sleeve as illustrated in Figure v3, or four sealing zones in the dual groove sleeve illustrated in Figure 5. For clarity in illustration the end depressions I8 and the intermediate depressions I6 have been drawn to an enlarged scale in Figures 3 and 5, but in actual practice make an almost imperceptible change in the contour of the interior surface of tube. Similarly, the compressed grooves a are nt exact representations but illustrate in a general way the changed shape resulting from compression.

By distributing the forces of compression acting on the sleeve'over a number of sealing surfaces, sucientdistortion of the sleeve is obtained to get the desired union with the ductile material of the tube Without distorting it to such a degree that it is hardened to any considerable extent which would thus render it more susceptible to breakage.

By developing a sealed union of the type shown in Figure 3 or 5, the series of circular impression Zones insure a positive seal even if the surface of the tube is marred or out of round. Further, the extent of the deformation of the tube is so controlled that the inner passage is not appreciably changed in size and hence no material impedance of flow through the tube results.

Through the use of resilient material in the compression sleeve which tends to straighten in the manner of a spring when there is any release of pressure, a lock-nut type of fastening is obtained which affords effective resistance to vibration influences. ency of nut I3 to move back along the thread of stem 8 is compensated by a following action in sleeve 'l Which maintains sufficient frictional engagement to prevent continuance of the loosening action.

To control the degree of distortion `in the form of the invention illustrated in Figures 4 and 5, the grooves are of uniform depth and positioned in uniform relation to the respective ends of the sleeve; Further, the curvature of the inner groove-defining surface is calculated to offset any buckling tendencies and direct the sleeve material into forcible engagement With the material of the tube.

Changes and modifications may be availed of Within the spirit and scope of the invention as defined in the hereunto appended claims.

What I claim and desire to secure by Letters Patent is:

l. In compression fittings, the combination with a tube of relatively ductile material which upon undue distortion tends to be changed in properties and thereby subject to fracture at or adjacent the fitting, of an encompassing sleeve in close engagement with the tube and means for compressing said sleeve longitudinally, said sleeve being relatively thick and having at least one radial groove extending sufficiently close to the inner surface of said sleeve so that the material of said sleeve beneath said groove will upon Consequently, any tendcompression be forced into deforming engagement With said tube, but deformation of said tube will be` insufficient to produce detrimental changes in the material of said tube, the material of said sleeve having a hardness greater than that of the'tube so that the ends of said sleeve upon compression tend to be forced into said tube, the outer periphery of said sleeve and said compressing means having cooperating surfaces sloped so as toA tend to forcethe ends of said sleeve into said tube, and the material of said sleeve also being sufciently resilient so that upon any reduction of the compressive forces, said sleeve ytendsto return to its initial shape, thereby exerting continued resistance pressure against said compression means.

2. In compression fittings, the combination With a tube of relatively ductile material Which upon undue distortion tends to be changed in properties and thereby subject to fracture at or adjacent the iittingof an encompassing sleeve in close engagement With the tube and means for compressing said sleeve longitudinally, said sleeve being relatively thick and having a plurality of longitudinally spaced radial grooves extending sufficiently close to the inner surface of said sleeve so that the material of said sleeve beneath the grooves upon compression will be forced into deforming engagement With said tube,-but deformation of said tube Will be insufficient to produce detrimental changes inthe material of said tube, the material of said sleeve having a hardness greater than that of the tube so that the ends of said sleeve upon compression tend to be forced into said tube, and the material of said sleeve being suiciently resilient so that upon any reduction of the compressive forces said -sleeve tends to return to its initial shape, thereby exerting continued resistance pressure against said compression means.

3. In compression fittings, the combination With a tube of relatively ductile material which upon undue distortion tends to be changed in properties and thereby subject to fracture at or adjacent `the fitting, of an encompassing sleeve in close engagement with the tube and means for compressing said sleeve longitudinally, said sleeve being relatively thick and having at least one radial groove extending sufficiently close to the inner surface of said sleeve so vthat the material of the sleeve beneath said groove upon compression will be forced into deforming engagement with said tube, but deformation of said tube will be insufficient to produce detrimental changes in the material of said tube, the material of said sleeve having a hardness greater than that of the tube so that the ends of said sleeve upon compression tend to be forced into said tube, and the material of said sleeve also being sufciently resilient so that upon any reduction of the compressive forces said sleeve tends to return to its initial shape, thereby exerting continued resistance pressure against said compression means.

CARL A. NORGREN. 

